Factors affecting outcome in liver resection.

BACKGROUND: Studies demonstrate an inverse relationship between institution/surgeon procedural volumes and patient outcomes. Similar studies exist for liver resections, which recommend referral of patients for liver resections to 'high-volume' centers. These studies did not elucidate the factors that underlie such outcomes. We believe there exists a complex interaction of patient-related and perioperative factors that determine patient outcomes after liver resection. We sought to delineate these factors.
METHODS: Retrospective review of 114 liver resections by a single surgeon from 1993-2003: Records were reviewed for demographics; diagnosis; type/year of surgery; American Society of Anesthesiologists (ASA) score; preoperative albumin, creatinine, and bilirubin; operative time; intraoperative blood transfusions; epidural use; and intraoperative hypotension. Main outcome measurements were postoperative morbidities, mortalities and length of stay (LOS). Data were analyzed using a multivariate linear regression model (SPSS v10.1 statistical analysis program).
RESULTS: Primary indications for resections were hepatocellular carcinoma (HCC) (N=57), metastatic colorectal cancer (N=25), and benign disease (N=18). There were no intraoperative mortalities and 4 perioperative (30-day) mortalities (3.5%). Mortality occurred in patients with malignancies who were older than 50 years. Morbidity was higher in malignant (15.6%) versus benign (5.5%) disease. Complications included bile leak/stricture (N=6), liver insufficiency (N=3), postoperative bleeding (N=2), myocardial infarction (N=2), aspiration pneumonia (N=1), renal insufficiency (N=1), and cancer implantation into the wound (N=1). Average LOS for all resections was 8.6 days. Longer operative time (p=0.04), lower albumin (p<0.001), higher ASA score (p<0.001), no epidural use (p=0.04), and higher creatinine (p<0.001) all correlated positively with longer LOS. ASA score and creatinine were the strongest predictors of LOS. LOS was not affected by patient age, sex, diagnosis, presence of malignancy, intraoperative transfusion requirements, intraoperative hypotension, preoperative bilirubin, case volume per year or year of surgery.
CONCLUSIONS: Liver resections can be performed with low mortality/morbidity and with acceptable LOS by an experienced liver surgeon. Outcome as measured by LOS is most influenced by patient comorbidities entering into surgery. Annual case volume did not influence LOS and had no impact on patient safety. Length of stay may not reflect surgeon/institution performance, as LOS is multifactorial and likely related to patient population, patient selection and increased high-risk cases with a surgeon's experience.